(1) Field of the Invention
The present invention relates to a method for efficiently producing a silicon hydride compound represented by cyclohexasilane in high purity, high purity cyclohexasilane that can be obtained thereby, a method for maintaining the purity of a silicon hydride compound such as a method for storing a silicon hydride compound and a method for cleansing an apparatus for a silicon hydride compound, and a method for treating an exhaust gas that allows a gas produced in a facility that handles a silicon hydride compound to be efficiently and safely exhausted.
(2) Description of Related Art
A silicon thin film is used for applications to solar cells, semiconductors and the like, and this silicon thin film has been conventionally prepared by a vapor deposition film-forming method (CVD method) using monosilane as a raw material. Recently, in place of the CVD method, a new production method using cyclic silicon hydride has been focused. This production method is a coating film-forming method (liquid process) in which a polysilicon hydride solution is applied to a substrate and then the substrate is subjected to calcination, and cyclopentasilane is used as a preparation raw material for the polysilicon hydride solution. Cyclopentasilane is commercially available, and has been reported to be polysilicon hydride by UV irradiation. However, cyclopentasilane requires multi-step synthesis using an expensive water-reactive reagent and a purification step for its production, and thus is very expensive.
Therefore, the present inventors have focused on cyclohexasilane as an alternate material for cyclopentasilane. As a method for synthesizing a silicon hydride compound represented by cyclohexasilane, it is known that it can be synthesized by an older known method of undergoing processes of cyclization, halogenation, and reduction, using diphenyldichlorosilane as a source (Hengge method, Angew. Chem. Int. Ed. Engl., 1977, 16, 403), a method of synthesizing a dianion complex using trichlorosilane and polyamine, and reducing this dianion complex (Japanese Patent No. 4519955), a method of reacting halosilane and an ammonium salt to obtain a cyclic silane intermediate, and reducing this cyclic silane intermediate (JP-A-2013-95697), and the like.